Principles for effective slides

Use slides as a complementary visual channel

If you examine the light table (a.k.a. slide sorter) view of my slide decks, they won’t make sense to you. Without my narrative, they’re useless. And yet, the slides employ the same components that an infodeck might.

• Colours, typography, and slide layouts that determine the overall template;
• and multiple components that include but aren’t limited to:
• text;
• images and illustrations;
• diagrams;
• charts;
• and videos.

Figure 1: Slides from a past talk.

The most important distinction between a presentation and an infodeck is what Neal Ford calls “control over the rate of knowledge exposition.” Unlike static infodecks, the builds (animations) and transitions in your presentation slides allow you to control that rate of knowledge exposition. You get to manage your audience’s cognitive load.

Slides also provide what Martin Fowler calls a “complementary visual channel” for your presentation. As a speaker, you’re conveying a message to your audience. The most important part of that message comes from your voice, expertise and stage presence. The slides shouldn’t make you redundant. Instead, they should enrich the message you’re already sharing using the audio channel.

Figure 2: You provide the words. The slides provide the visuals and some reinforcing words.

The idea of a complementary visual channel becomes even more important when you reflect on how we learn. In their 2016 book, E-Learning and the Science of Instruction, Clark and Mayer establish the “multimedia principle”; i.e. people learn better from words and graphics than from words alone. We encode words and visuals in different parts of our brains. When you provide the words and your slides provide the visuals, your audience benefits from dual encoding. Your message becomes more memorable than if you provided words alone, or worse, words similar to those on your slide.

Slides aren’t the only visual channel possible. Tools like Prezi, Mural and Miro let you create a giant canvas for your talk, and you can pan and zoom into specific parts of it to support your presentation. However, since slideware is more ubiquitous in corporations, we’ll focus on the 16x9 slide format for the rest of our discussion.

Couple slides tightly with the speaker

When we think of slides as the visual channel for our presentations, another principle becomes apparent — your visuals must tightly couple with what you’ll say, without repeating what you’ll say. After all, you’ll present to a literate audience, and they can read faster than you read aloud.

Take a look at the slide below. It’s an example of the standard-issue slides you’ll see in a corporate infodeck. As a standalone reading artefact, it’s passable. As a presentation slide, it’s a disaster. By the time you start with the first point, your audience will have already speed-read the entire page. Martin Fowler calls this phenomenon “stealing the narrative,” because slides like these make you lose control of your story.

Figure 3: Audiences can read such slides faster than you.

The above slide is an example of why you can’t present an infodeck, no matter how elegant the design. Don’t beat yourself up when your eyes glaze over at the sight of such slides. The above example also begs the question of why you’re there in the first place.

If the slides can stand by themselves, why are you up there in front of them? Just hand out the slides and sit down!

-- David S. Rose, venture capitalist

What’s the alternative, then? If I were presenting the content on the slide above, I’d break up the visuals to match my narrative. The single slide above would split into the 31 visuals below, driven by slide transitions and animations. The words on screen will appear as a summary of what I say, either in sync with my speech or right after I’ve made my point.

Now, if you were the narrator, you might choose a different split. There lies the disadvantage of well-designed slides that serve as a complementary visual channel. It’s difficult to share your slides with someone so they can present your topic. Effective slides often reinforce a speaker’s storytelling style, pace, and anecdotes. They’re fine-tuned to the speaker’s idiosyncrasies. While you can use another speaker’s slides, you’ll have to tune them to your delivery approach.

Practice minimalism by default

When you design slides that are in sync with your speech, you can’t design heavy, wordy slides. A single slide can have many elements, but you must control the rate at which you reveal those elements, so you don’t let your audience race ahead of you. So, I suggest being minimalist by default when constructing your slides. Take Antoine de Saint-Exupéry's quote to heart.

Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.

-- Antoine de Saint-Exupéry

When designing slides for your presentation, think in snapshots and be ruthless about how little each snapshot reveals and how much it adds to a previous snapshot. Invariably, you’ll end up with a deck with many slides, and as I’ve said earlier in the series, the number of slides doesn’t matter.

The example below will help make my point. These are slides I presented to a C-suite audience to explain developer relations. It took me two minutes to get through 14 snapshots, all related to the same base diagram. When you thumb through the slides, you’ll see that I reveal each part of the framework in a new snapshot. I then overlay the diagram with an example of that aspect of developer relations, then move back to the main diagram and reveal the next aspect.

Designing the slides this way enabled me to manage my audience’s cognitive load and the rate at which I presented information.

To practice minimalism, think of slides as billboards. In her book, slide:ology, Nancy Duarte says that slides are “glance media” and share much in common with billboards. You want each visual or snapshot to be easy to grok in a few seconds. If a billboard takes too long to understand, it could cause an accident on the street. If a slide takes too long to process, well, you might have a cognitive accident to deal with.

Figure 4: Slides have a lot in common with billboards.

Treat slides as integrated visuals

If your audience is thinking about your slides, they’re not paying attention to your message. This is why I never let anyone else control my slides. “Next slide, please” is the easiest way to distract your audience from the message and have them think about your slides.

The most effective slides often don’t feel like a collection of components. They feel like integrated visuals that, along with the speaker, create a cinematic presentation experience. The audience doesn’t sense how one slide transitions to another or how you’re using layers and builds in your visuals, and they shouldn’t have to. Here’s a three-minute video presentation that may help make my point.

The above presentation is simple. It uses only a few icons, text and images. But it’s difficult to say where one slide begins and another ends. And that’s by design. The more continuity we create across our slides, the less salient the number of slides and their construction. The less salient these inner workings are, the more salient our narrative can be.

Use the visual channel to say a thousand words

A year or so back, I delivered a short talk about AI and a “perpetual beta” mindset. I won’t get into the details of the talk, but I’ll talk you through the slides you see below. In my presentation, I explained how AI models on cameras use a split-second heuristic to autofocus on a subject's eyes — human or animal. I then cycled through many subjects the camera eye-detects with ease and said, “What happens when an animal has eyes all over their body?” On cue, a leopard’s photo appeared on screen. The audience could see why the camera fails to autofocus. That punchline, combined with the blurry photo of a leopard, got me a good laugh from the audience and helped me make the point that even mature AI is fallible.

When you deliver a presentation, you often assume the role of an educator. Visuals can help you add a layer of entertainment to your education. Notice how little text I use in the above example. I let the photographs do most of the talking. At the end of the segment, one of the photos also adds comic relief. 13 slides, a minute of talking, and 13 photos that say more than I ever could without the slides.

This isn’t to say that text is unnecessary. Text can reinforce or summarise what you say and help you label parts of the visual. Saying a picture speaks a thousand words doesn’t mean pictures don’t need explanation or that using words on screen signals failure. As Dan Roam explains,

A good picture substitutes for the thousand words that are the least necessary.

-- Dan Roam

The trap to avoid is letting the text substitute for you, the presenter. Remember, the slides are a complementary visual channel.

Never send the slides

All this brings us to the series title. I meant for it to be provocative, but I also mean for it to be a principle. If your slides serve as a visual channel that reinforces what you say, they can’t stand alone. If you send them out in advance, you’ll only undermine your storytelling and the humour, intrigue and impact you’d have planned for your presentation. So, I don’t recommend sending your slides in advance. That said, I want to offer alternatives.

If you want to prepare your audience, send them prep notes. Corporations are busy places, and people struggle to prepare in advance, so the more succinct your prep materials, the more likely people will consume them. One page, a short email, or even a structured instant message can be preparation enough.

If you want to align with your co-presenters, colleagues, or boss before the presentation, then do a dress rehearsal. If a presentation is high-stakes and you don’t have time for a live rehearsal, you could record yourself giving the presentation and send the video out to get feedback. Such feedback can help you solidify your prep and get feedback to tighten your narrative and delivery. By getting your colleagues and boss onside before an important presentation, you’ll be able to seed your audience with supporters — a pattern Ford, McCollough and Schutta call the “Greek chorus”.

If you want your audience to have some resources handy when you present, create reference materials. You can hand these out as prints before you begin your presentation, or create an online resource. When I deliver presentations online, I often share resources in the chat during the presentation to manage my audience’s cognitive load. The minimalism principle applies here too. Reference materials are a distraction. The more focused they are, the more effective they’ll be.

And finally, if you want to give your audience something to take away, create a handout that summarises your talk. If you’re diligent about writing presenter notes, a PDF of your slides, juxtaposed with your presenter notes, can serve as a handout for your talk. If I’m speaking at a conference, I often create a single-page takeaway for my audience. When Martin was active on the conference circuit, he shared talk notes for his presentations.

Not every talk needs so many artefacts. It’s your call, based on what you know of your audience. For example, when I presented research findings on the state of remote work at Thoughtworks, I didn’t send any prep notes, but I did create a handout and a dashboard where my audience could play with the raw data. Since the dashboard would be a distraction during the talk, I shared it towards the tail end to let the data provoke questions from the audience.

Figure 5: One presentation. Three artefacts.

Is the approach I’m suggesting a lot of work? Perhaps. If your story is worth telling, you care about your audience’s experience engaging with you and the impact you make, then it's a worthwhile effort.

Now, do I never send my slides? Never say never, right? There are exceptions. Sometimes my colleagues want to adapt my slides to their narrative. Other times, people are curious about how I built my slides. In such situations, I do share my slides. No problem. Use your judgment to make exceptions when necessary.

Rewrite the rulebook

You’ll notice that I’m asking you to throw away the rulebook that says you should have one slide for every two minutes of speech, or the one that says you need six bullets per slide with no more than six words per bullet. Those are the death-by-PowerPoint rules. Our principles are different.

• As presenters, we seek to control the rate of knowledge exposition.
• Slides serve as a visual channel to complement the speaker.
• Slides and speakers are tightly coupled.
• The number of slides doesn’t matter.
• Be minimalist by default.
• Treat slides as integrated visuals, not a collection of components.
• Never send the slides.

And finally, as I explained with the photographs in the “perpetual beta” presentation, we want the visual channels to say a thousand words and blend education and entertainment.

Now that I’ve laid down some principles, let's change track to “how to” build effective slides. In the next post, we’ll begin with the fundamentals of colours, typography and layouts.